package mypack;

public class StaticChange {

    public static int[] IP = {
        58,50,42,34,26,18,10,2,
        60,52,44,36,28,20,12,4,
        62,54,46,38,30,22,14,6,
        64,56,48,40,32,24,16,8,
        57,49,41,33,25,17, 9,1,
        59,51,43,35,27,19,11,3,
        61,53,45,37,29,21,13,5,
        63,55,47,39,31,23,15,7
    };

    public static int[] RIP = {
        40, 8, 48, 16, 56, 24, 64, 32,
        39, 7, 47, 15, 55, 23, 63, 31,
        38, 6, 46, 14, 54, 22, 62, 30,
        37, 5, 45, 13, 53, 21, 61, 29,
        36, 4, 44, 12, 52, 20, 60, 28,
        35, 3, 43, 11, 51, 19, 59, 27,
        34, 2, 42, 10, 50, 18, 58, 26,
        33, 1, 41, 9,  49, 17, 57, 25
    };

    /*
      **置换选择P1,密钥由64位变56位.
      **书上没有这个过程，直接是56位密钥.
    */
    public static int[] P1 = {
        57,49,41,33,25,17,9,1,
        58,50,42,34,26,18,10,2,
        59,51,43,35,27,19,11,3,
        60,52,44,36,63,55,47,39,
        31,23,15,7,62,54,46,38,
        30,22,14,6,61,53,45,37,
        29,21,13,5,28,20,12,4
    };

    //置换选择P2，密钥由56位变成48位
    public static int[] P2 = {
        14,17,11,24,1,5,
        3,28,15,6,21,10,
        23,19,12,4,26,8,
        16,7,27,20,13,2,
        41,52,31,37,47,55,
        30,40,51,45,33,48,
        44,49,39,56,34,53,
        46,42,50,36,29,32
    };

    //E置换，将32位输入数据扩展为48位
    public static int[] E = {
        32,1,2,3,4,5,
        4,5,6,7,8,9,
        8,9,10,11,12,13,
        12,13,14,15,16,17,
        16,17,18,19,20,21,
        20,21,22,23,24,25,
        24,25,26,27,28,29,
        28,29,30,31,32,1
    };

    //P置换,f函数的最后一步 
    public static int[] P = {
        16,7,20,21,29,12,28,17,1,15,23,26,5,18,31,10,
        2,8,24,14,32,27,3,9,19,13,30,6,22,11,4,25
    };

    //S盒
    public static Integer[][] S = {
        {
            14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7,
            0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8,
            4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0,
            15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13
        },
        {
            15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10,
            3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5,
            0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15,
            13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9
        },
        {
            10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8,
            13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1,
            13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7,
            1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12
        },
        {
            7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15,
            13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9,
            10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4,
            3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14
        },
        {
            2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9,
            14,11,2,12,4,7,13,1,5,0,15,10,3,9,8,6,
            4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14,
            11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3
        },
        {
            12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11,
            10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8,
            9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6,
            4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13
        },
        {
            4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1,
            13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6,
            1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2,
            6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12
        },
        {
            13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7,
            1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2,
            7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8,
            2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11
        }
    };
    
    //48位变32位,S盒运算
    public static StringBuilder Schange(StringBuilder ss) {
        StringBuilder u = new StringBuilder();
        for(int i = 0; i < 8; i++) {
            String tmp = ss.substring(i*6, (i+1)*6);
            int r = 2*(tmp.charAt(0) - '0') + (tmp.charAt(5) - '0');
            int c = Integer.parseInt((String)tmp.substring(1,5), 2);
            u.append(numberChange.toBinary(S[i][r*16 + c], 4));
        }
        return u;
    }
    
    //IP置换
    public static StringBuilder IPchange(StringBuilder ss) {
        return change(ss, IP);
    }

    //P1置换
    public static StringBuilder P1change(StringBuilder ss) {
        return change(ss, P1);
    }

    //P2置换
    public static StringBuilder P2change(StringBuilder ss) {
        return change(ss, P2);
    }

    //E置换
    public static StringBuilder Echange(StringBuilder ss) {
        return change(ss, E);
    }

    //P置换
    public static StringBuilder Pchange(StringBuilder ss) {
        return change(ss, P);
    }

    //逆IP置换
    public static StringBuilder RIPchange(StringBuilder ss) {
        return change(ss, RIP);
    }

    //因为几个置换大同小异，用一个函数管理
    private static StringBuilder change(StringBuilder ss, int[] pp) {
        StringBuilder u = new StringBuilder();
        for(int i = 0; i < pp.length; i++) {
            u.append(ss.charAt(pp[i] - 1));
        }
        return u;
    }

    //左循环移位，l 为移动位数
    public static StringBuilder leftMove(StringBuilder ss, int l) {
        ss.append(ss.substring(0, l));
        ss.delete(0, l);
        return ss;
    }

    public static StringBuilder rightMove(StringBuilder ss, int l) {
        if(l == 0)
            return ss;
        return new StringBuilder(ss.subSequence(ss.length() - l, ss.length())).append(ss.subSequence(0, ss.length() - l));
    }

    /*
      **f函数,kk为48位的密钥，ss为右32位。先将ss扩展到48位
      **再与48位密钥异或，通过S盒转为32位，通过P置换输出结果
    */
    public static StringBuilder Ffuction(StringBuilder ss, StringBuilder kk) {
        StringBuilder u = Echange(ss);
        u = stringXOR(u, kk);
        u = Schange(u);
        return Pchange(u);
    }

    //异或,ss和kk长度相同
    public static StringBuilder stringXOR(StringBuilder ss, StringBuilder kk) {
        StringBuilder u = new StringBuilder();
        for(int i = 0; i < ss.length(); i++) {
            if(ss.charAt(i) == kk.charAt(i))
                u.append('0');
            else
                u.append('1');
        }
        return u;
    }

    //一轮操作,key是这一轮的密钥，返回新的left和right
    private static StringBuilder[] oneTurn(StringBuilder left, StringBuilder right, StringBuilder key) {
        StringBuilder newright = StaticChange.stringXOR(left, StaticChange.Ffuction(right, key));
        return new StringBuilder[]{right, newright};
    }

    //64bit明文完整的加密过程,16轮
    public static StringBuilder encryptProcess(StringBuilder plain, StringBuilder[] key) {
        plain = StaticChange.IPchange(plain);
        StringBuilder left = new StringBuilder(plain.subSequence(0, 32));
        StringBuilder right = new StringBuilder(plain.subSequence(32, 64));
        for(int i = 0; i < 16; i++) {
            StringBuilder[] tmp = oneTurn(left, right, key[i]);
            left = tmp[0];
            right = tmp[1];
        }
        return StaticChange.RIPchange(right.append(left));
    }

    //64bit密文完整的解密过程,16轮
    public static StringBuilder deciProcess(StringBuilder secret, StringBuilder[] key) {
        return encryptProcess(secret, key);
    }

    public static void main(String[] args) {
        StringBuilder[] key = Key.EncrykeyGenerator(new StringBuilder(args[0]));
        System.out.println(encryptProcess(new StringBuilder(args[1]), key));
    }

}